Electrically conductive cellulose containing materials can be based on the mixture of cellulose containing matrix and conductive particles (fillers) embedded into this matrix. In the former case the matrix can also contain organic or inorganic additives and the electrically conductive particles be either carbon particles, metal particles or metal oxide particles. The materials can also be directionally conductive.
Conductive papers are proposed for applications in energy storage.
In PNAS 2009 106 21490 is described how conductive paper is prepared by using commercially available paper and conductive carbon and silver particles. This paper act as a capacitor with very high capacitance (200 F/g) and specific energy (7.5 Wh/kg). This stems from the fact that the material is significantly lighter than corresponding capacitors with metal framework.
Conductive papers are proposed for applications in electromagnetic interference (EMI) shielding.
In Compos. Sci. Tech. 2010 70 1564 is described how carbon nanotube/cellulose composites incorporated into the paper making lead to a paper with EMI shielding properties. Typically 10 wt-% carbon content is required to achieve a composite paper with sufficient 20 dB far-field EMI shielding effectiveness.
Conductive papers contain typically large amount of conductive particles.
In U.S. Pat. No. 3,367,851 is described how electrically conductive paper can be prepared from electrically conductive carbonaceous fibers and wood pulp. The fraction of conductive component varied from 2 to 35 wt-%.
In U.S. Pat. No 4,347,104 is described the electrically conductive paper with the fraction of conductive carbonaceous component from 1 to 35 wt-%.
In U.S. Pat. No. 3,998,689 is described a carbon fiber paper where the ratio of carbon fibers falls in the range of 40-90 wt-%.
One problem with these techniques is that one has to use lots of conductive fillers like carbon. These relatively high fractions of conductive fillers are problematic for a variety of reasons. Another problem is that the sizes of the conductive fibers are limited. Long conductive carbon fibers would be beneficial for applications seeking to reduce electromagnetic interference. However, if the fibers are too long one can have problem getting the fibers dispersed.